Process of making articles having the appearance of pearl



Patented Apr. 20, 1937 UNITED STATES.

c c 2,078,001 c p c PROCESS OF MAKING ARTICLES HAVING THE APPEARANCE F PEARL Jacob Lurie, Springfield, Mass, assignor to The 'Fiberloid Corporation, Indian Orchard, Mass., a corporation of Massachusetts I No Drawing. Application June 17, 1935,

' Serial No.,26,933

3' Claims. (CI. 91-58) My' invention relates to the manufacture of articles having the general appearance of motherof-pearl and similar materials whether natural or artificial, the surface of which havefpe'culiar 5 light effects caused by the 'presence'of minute particles either of fish scale substance or substitutes therefor, or other finely divided substances such as aluminum and bronze powders, and the so-called artificial pearl substances which reflect or transmit light in different directions and in varying amounts according totheirposition in the material, such substances being conveniently called pearly substances. It is believed that the pearl effect from such materials is relatedto the position of the individual particles with respect to each other, and to the surface of the sheet. In this art, thisrelation has been referred to as orientation. Heretofore the maximum efiect has been accomplished byextruding thefmixture or the plastic material containing the pearlysubstance through a suitable orifice, then cutting the material into small pieces;' laying them at random angles and compressing into a solid block which is then'sheeted in the usual Way.

I have discovered, however, that if a liquid conveniently called a carrier and containing the pearly substance is floated on thesurface of a bath of another liquid, as for instance water, the particles of the pearly substance may be transferred to an article by bringing the surface of the article into contact with the surface of the carrier film as it floats on the bath, and the layer of material thus transferred to the surface of the article will have the optical effect of pearl mate-- rial. The film is so flexible and plastic that it conforms to the shape of the surface of the article even though'it be irregular, as forexample a tooth brush handle, knob or spool. ;:-,The whole or only a part of the surface of the article may be 40 coated.

This process makes it possible to use a. relatively small amount of the pearly substance because it is applied to the surface of the article only and is not distributed throughout the whole mass.

Since these pearly substances are generally expensive, this results in substantial saving. Furthermore, by choosing the color and nature of the material of which the article to be coated is made, very pleasing and unusual efiects can be produced.

For instance, transparent plastic may be employed and this may be colored either uniformly or in varying degrees or colored, translucent, opaque or variegated materials may be employed. Likewise articles of other substances, for instance,

wood or metal, may be coated by my novel meth- 0d. In such case, thecoating mayioften befacilitated by the application of suitable priming coats. When desired a transparent protective-coat may be applied. I I

, The carrier liquid from which the is formed is any liquid-which will retain the pearly substance in suspension and will adhere to the article to be coated In practice it is convenient to use a lacquer ,such as a cellulose ester or ether lacquerwhich may itself be transparent or may be colored as required for the particular efiect to be produced. c

The pearly materialin the coating vmaybe any of a number of substances. For instance, pearl essence obtained from fish scales, certainmetallic powders, such as aluminum powder, bronze powder and the like, and in fact any finely, divided -substance which producesitherequired light effect. For convenience, I employ the term pearly substance to cover all such materialsii- The bathon which the mixture of carrier liq,- uid and pearly substance isfloated is some liquid which is not-a solvent for the solid constituents of the carrier liquid, although it maybe-miscible with one or more of the solvents used'to make. up the carrier liquid. For ordinary purposes water is satisfactory; 1

The article -t o -be coated maybe a sheet which is subsequently cut up;or formed into the final. product or it may be a completely finished article, as for instance atooth brush handle. 'When aformed article is to be coated this can be done-by slowly submerging the article in the bath on which the mixture floating. When a sheet is tob'e coated, the coating maybe done by bringing the surface of thesheet progressively into contact with the mixture floating on the bath, additional coating mixture being supplied as required.

The nature of the ingredients of the carrier liquid affects the pattern produced; thus acetone tends to produce a more marked pearl mottle than either ethyl acetate or butyl acetate, while the addition of diluents, such as coal tar solvents, petroleum naphthas or alcohol, also changes the appearance of the mottle noticeably, andcamphor produces a peculiar pattern.

The effect of'a solvent seems to vary with its rate of evaporation and the extent of its miscibility with water. This indicates that the pattern of the pearl mottle is dependent upon the interfacial forces set up between the lacquer and the water phases.

As an illustration of one method of practicing the process comprising my invention, the following procedure for producing sheets having a pearly surface appearance may be followed. The base material, whatever that may be, is formed into a sheet or'sheets of the desired size and thickness, and may even be in the form of a continuous sheet or web. It may be'made of transparent, translucent or opaque stock, and may be colored with varying colors as required. Very attractive effects are producedby using mottled sheet stock. I then mix a transparent pyroxylin lacquer and natural pearl essence, for,

example in the proportion of "5 to 10 parts of essence to 100 parts of lacquer. This lacquer may be composed, for example, as follows: 1 pound of second nitrocellulose, pound dibutyl phthal- The solselves'in patternsl' After the film is formed on the bath, the surface of the sheet is brought into contact with the film thereby transferring the film with the pearly substance therein to the surface of the sheet. In practice it is desirable after the coating layer has been allowed to form on the surface of the bath to allow the solvent in the coating material to evaporate somewhat thereby causing thecoating to harden slightly before-the article to be coated is brought in contact'with it. If this is done it is also desirable to soften the surface of the article to be coated by applyingto it by dipping, spraying or fuming a littleiof assuitable solvent. This activates the surface and causes the coating to adhere more 40 satisfactorily. In practice, I find that by this procedure more satisfactory results are'obtained, particularly since there isless trouble with air bubbles This method which includes hardening a floating coating and then applying'it; to an article, the surface of which has preferably been activated by the application of asolvent, has application to other articles-than those which are to be given a, pearl-like appearance and therefore ismade the subject of a separate application and isnot claimed herein.-

,If an article such as a tooth brush handle, knobror spool is to be coated, the same procedure is followed except that the'article, if it be of a material such as wood or 'metal, may be first coated with a. suitable primer or under coat to which the ornamental coating will adhere. The

priming or under coat may be omitted according to circumstances. After the article is prepared, the, surface being activated by the application of solvent or not as required, the article is slowly submerged in the bath on which floats the ornamental coating which has preferably been allowed to harden slightly by the evaporation of solvent and preferably removed therefrom through a part of the surface of the bath which is not covered by a film. The evaporation of solvent in this case, however, should not be allowed to proceed too far. It is important that the coating be still so flexible and plastic that it con forms readily to the surface of the article and adheres strongly thereto, producing a uniform coatover the whole article. Any other convenient method of bringing the surface of the article or the portion thereof which it is desired to coat intocontact with the layer of coating material floating on the surface of. the bath may be employed.

A'fter coating, the sheets are dried and will be found to have an excellent pearl effect with the use of a relatively smallamount of pearly mateture on a bath of liquid in a sufiiciently thin'film to produce orientation of the pearly substance and thereby orienting the particles of the pearly substance, andthen bringing the article to be coated'into contact with the mixture.

2 The process ofmaking imitation pearl sheets which -consists in mixing a pearly substance with a suitable carrier liquid andin an amount to produce orientation, floating the mixture on a bath of water to form a carrier film of suflicient thinness to produce orientation of the pearly substance andbringing a sheet of cellulosic material into contact with the carrier film. r

3. The process of making imitation pearl tooth brush handles which consists in mixing a pearly substance with a suitable liquid to form a carrier film and in an amount to produce orientation, floating the mixture on a bath of liquid as a sufficiently thin filmto produce orientation of the pearly substance and bringing the surface of the tooth brus'hhandlc into contact with the carrier film.

JACOB LUR-l'iii. 

